BBA Flagon SR - Soprema

6 Properties in relation to fire
6.1 When tested in accordance with BS 476-3 : 1958, a system comprising a 19 mm thick exterior grade
WBP plywood, a high-density polythene vapour barrier, a 50 mm polyurethane insulation board mechanically
fixed, and a layer of Flagon SR1.2 mechanically fixed achieved a rating of EXT.F.AB.
6.2 The membranes when used in protected or inverted roof specifications, including an inorganic covering listed in the
Annex of Commission Decision 2000/553/EC, can be considered to be unrestricted under the national Requirements.
6.3 The designation of other specifications should be confirmed by:
England and Wales — Test or assessment in accordance with Approved Document B, Appendix A, Clause 1
Scotland — Test to conform to Mandatory Standard 2.8, Clause 2.8.1
Northern Ireland — Test or assessment by a UKAS accredited laboratory, or an independent consultant with
appropriate experience.
6.4 In the opinion of the BBA, when used in irrigated roof gardens or green roofs, the use of the membrane will be
unrestricted under the national Requirements:
England and Wales — Requirement B4(2)
Scotland — Mandatory Standard 2.8, Clause 2.8.1
Northern Ireland — Regulation E5(b).
6.5 If allowed to dry, the plants used may allow flame spread across the roof. This should be taken into consideration
when selecting suitable plants for the roof. Appropriate planting irrigation and/or protection should be applied to
ensure the overall fire-rating of the roof is not compromised.
7 Resistance to wind uplift
7.1 The resistance to wind uplift of a mechanically-fastened waterproofing layer is provided by the fixing bar and
fasteners passing through the membrane into the substrate. The number and position of fixings will depend on a number
of factors including:
wind uplift forces to be restrained
pull-out strength of the fasteners
tensile properties of the membrane
appropriate calculation of safety factors.
7.2 The wind uplift forces are calculated in accordance with BS EN 1991-1-4 : 2005 and the UK National Annex. On
this basis, the number of fixings required should be established using a maximum permissible load of 0.4 kN per fixing.
7.3 Wind uplift load results from testing on an installed system are:
Load per fixing (N) 1000
Corrected load per fixing (N) 461
7.4 The Certificate holder provides a design service which takes into account all the relevant information supplied and
gives assistance for the preparation of drawings for the positioning of fastening bars or washers, and the number of fixings
required. The Certificate holder takes the liability for the calculations of the design of the mechanically fastened system.
7.5 The ballast requirements for inverted roof systems should be calculated in accordance with the relevant parts of
BS EN 1991-1-4 : 2005 and the UK National Annex. When using gravel ballast the system should always be loaded
with a minimum depth of 50 mm of aggregate. In areas of high-wind exposure, the Certificate holder’s advice should
be sought. Alternatively, concrete slabs on suitable supports can be used.
7.6 The soil used in roof gardens and ballast on inverted/protected roofs must not be of a type that will be removed,
or become delocalised due to wind scour experienced on the roof.
7.7 It should be recognised that the type of plants used in roof gardens could significantly affect the expected wind
loads experienced in service.
8 Resistance to foot traffic
Results of tests indicate that the systems can accept the limited foot traffic and light concentrated loads associated with
the installation and maintenance. Reasonable care should be taken to avoid puncture by sharp objects or concentrated
loads. Where traffic in excess of this is envisaged, such as maintenance of lift equipment, a walkway should be
provided, for example, using concrete slabs supported on bearing pads or Flagon Walkway.
9 Resistance to penetration of roots
Results of tests on the Flagon SR1.5 membrane indicate it is resistant to root penetration and can be used in a roof
waterproofing system for roof gardens and green roofs.
10 Maintenance
10.1 Systems must be the subject of annual inspections and maintenance to ensure continued performance.
Exposed membrane must be free from the build-up of silt and other debris and unwanted vegetation must be cleared.
Page 5 of 10